Jab 2200 and Thruster T600

[Guest TOSGcentral]

Via the TOSG network I have received a copy of a Service Bulletin (#TAS/SB12) issued by Thruster Air Services (the independent UK factory) regarding information received from the Jabiru factory in Oz about the Jabiru 2200 motor.

 

The information from Oz stated that quote they had identified a resonant issue at around 2200 rpm. Continued operation at around this level they say may lead to problems with the flywheel bolts and the crankshaft

 

Consequent to this, inspection of two high time T600/J2200 engined trainers showed them to be developing cracks on their engine mounts.

 

The cause of the cracking is being attributed to fatigue at the moment but there is no conclusive evidence that the vibration band is the cause.

 

Nevertheless Thruster Air Services have stated that J2200 engined Thruster should not be cruised between 2100 and 2300 rpm.

 

I have sent a copy of the SB to the RAA Tech Manager (if he has not already got one) but am posting here as it may be of more than passing interest to some readers.

 

Aye

 

Tony

 

 

[Ultralights]

will this issue only effect Thruster aircraft? or will the same Engine create similar problems in other aircraft?

 

 

[Guest TOSGcentral]

I cannot give an answer one way or another to that question.

 

What is evident from the SB is that Jabiru were concerned about engine damage and Thruster UK were concerned about engine mounts cracking.

 

If the engine has a vibration band then that is inherent in the engine no matter what it is fitted in. Whether any such vibration would be responsible for inducing fatigue cracking would be dependent on the form of mounting to which the motor is bolted.

 

The T600 & V600 mounts are formidable affairs and are certainly not short of strength!

 

Vibration bands are not uncommon in motor types and are a nuisance as they usually occur at the RPM range you may like to cruise at. You should also note that the effect is not readily apparent to the pilot and does not give any outward signs such as your fillings being shaken loose. It is more a form of harmonic reasonance within the motor itself.

 

Tony.

 

 

[Yenn]

From memory Jabiru recommend not running between 2000 and 2400rpm because of vibration problems. I can't find the relevant notice at short notice but I have it somewhere. I may be wrong with the rev range but it is approximately correct.

 

Ian

 

 

[rick-p]

I have read all the observations here on this issue but still there does not seem to be any closure in respect of the matter. Is it a genuine problemor is it just another Jabiru motor hypothesis? I would really like to know as my new ship is powered by a 2200 and the alleged guilty rev range is just what my ship thrives on, (economy cruise).If someone has the correct verdict would they mind to enlighten me,thanks. Rick p.